The project contains write set replication patches for MariaDB maintained by Codership team.

This patch implements hooks inside MariaDB storage engines, which can be used to build external replication system for MariaDB servers. The replication system built on these hooks can be asynchronous or synchronous and have single or multi-master support.

The replication hooks provide management of transaction write sets:

* populating of write sets, in the sending side
* applying of write sets, in the receiving end

The applying happens by high priority transaction(s), the lock manager has been modified to give preference to dedicated high priority MariaDB threads.

There are also calls for providing "total order isolated" processing of certain SQL statements. This feature guarantees that each MariaDB server in the cluster process the SQL statement in the same order and uninterrupted. .e.g. all DDL statements need to be processed isolated, to maintain data consistency in the cluster.